1. Field of the Invention
The present invention relates to personal navigation device (PND) navigation, and more particularly, to a method of routing a first PND away from a second PND.
2. Description of the Prior Art
A number of navigation methods have been employed over the centuries by sailors desiring to go from one place to another without getting lost on the way or passing through dangerous waters. Whereas in the past, navigation was typically of interest to navigators on marine vessels, as more advanced navigation systems are developed, drivers, hikers, and tourists are rapidly adopting Global Navigation Satellite System (GNSS) receivers as aids in their travels.
One key to navigation is positioning, or the art of knowing precisely where one is at any given moment. In the past, positioning was accomplished through use of a sextant, which measures angular positions of celestial bodies relative to the horizon. Today, positioning can be accomplished with fair accuracy by GNSS receivers. Currently, only the NAVSTAR Global Positioning System (GPS) developed by the United States Department of Defense offers comprehensive positioning satellite coverage around the globe, though other systems should become operational by the year 2010.
A typical GPS receiver will include an antenna for receiving electrical signals transmitted by GPS satellites, and positioning circuitry for determining a position of the GPS receiver from the electrical signals, and generating corresponding position data. The antenna can be integrated into the GPS receiver, or can be connected externally through a wire. A personal navigation device (PND) can integrate the GPS receiver and further means for providing functions that use the position data generated by the GPS receiver. Typically, the PND can be a standalone mobile device, or can be integrated into an automobile as another instrument on the dashboard. The standalone mobile device can also be adapted for use in an automobile through a mount, which can be attached to the automobile through suction cups or other more permanent means.
The PND will typically include an internal map, which can be used in conjunction with the position data to determine where the PND is located on the map. Based on this information, a navigator function of the PND can calculate a route along known roads from the position of the PND to another known location.
As the PND becomes more sophisticated, the position data and route data may be shared between PNDs, allowing for new applications and functionalities that should be explored further. Please refer to FIG. 1, which is a diagram of performing routing in the PND according to the prior art. Two routes are shown in FIG. 1. A first route R1 is determined for a first PND, and a second route R2 is determined for a second PND. As shown in FIG. 1, the second route R2 overlaps with part of the first route R1. However, in the prior art, if the user of the first PND does not want to run into the user of the second PND, it is likely that an unwanted encounter will occur.